This research is directed towards increasing understanding of normal and abnormal erythrocyte and leukocyte metabolism and towards elucidating the pathogenesis of both hereditary and acquired homolytic anemias. The enzymatic behavior and constituents of separated red cells and white cells are being investigated in hemolysates and homogenates, before or after incubation with added substances by spectrophotometric methods in most instances. Metabolic studies of the pentose phosphate pathway and recycling in intact cells are being performed with radioactive labeled compounds utilizing the ionization chamber method. The objectives are to extend knowledge of pyruvate kinase deficiency and other enzyme deficiency hemolytic anemias with particular reference to genetic polymorphism, to define new enzymopenic hemolytic disorders, to examine further the role of the pentose phosphate pathway in various enzyme deficiency hemolytic anemias, especially during oxidant forms of stress, to enlarge understanding of certain acquired hemolytic anemias,k and to utilize as metabolic models the red cell and white cell, since they are easily sampled and may reflect metabolic abnormalities or changes occurring in the other less accessible tissue due to an hereditary metabolic defect, systemic disease, or administration of drugs. These studies should provide a better basis for understanding normal and abnormal red cell and white cell metabolism and lead to improved diagnosis and therapy of clinical disease.